Case Study 6Harry Kellermier, M.D.

Question 1Describe this T1 weighted MRI and give a radiologic differential.

AnswerDestructive lesion involving the clivus.  The radiologic differential includes chordoma, chondrosarcoma, and less likely metastasis.

Question 2Describe the microscopic findings.

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AnswerThis neoplasm is composed of hepatoid trabeculae of epithelioid cells with eosinophilic and bubbly cytoplasm in a myxoid matrix.  Some areas appear somewhat chondroid.

Question 3What is your histologic differential diagnosis?

AnswerChordoma, Chondrosarcoma, Adenocarcinoma

Question 4What immunostains would you order?

AnswerKeratins (AE1/AE3, Cam 5.2, or Pankeratin), S100, EMA, CEA

Question 5Based on the following immunohistochemical results, what is your diagnosis?

AE1/AE3

CAM5.2

PANKERATIN

EMA

S100

Answer1. Chordoma - Keratin positive, EMA positive, S100

positive, CEA negative2. Chondrosarcoma would be S100 positive,

keratin negative, EMA negative; Adenocarcinoma would be Keratin positive, EMA positive, CEA positive, and usually S100 negative.

Question 6What are the "bubbly" cells called in this tumor?

AnswerPhysaliphorous cells (Greek - bubble bearing)

Question 7From what developmental structure does this tumor arise?

AnswerThe notochord

Question 8What anatomic locations do they typically involve?

AnswerChordomas involve the midline of the axial skeleton.  30%-40% involve the base of the skull (clivus in the region of the spheno-occipital synchondrosis), approximately 49% involve the sacrum, and approximately 15% involve the vertebral column, usually the cervical spine.

Question 9What is the name of the benign developmental remnant of notochord that histologically resembles a chordoma?

AnswerEcchordosis physaliphora.  These lesions are small, well-circumscribed gelatinous masses adherent to the brainstem.  They behave in a benign manner.

Question 10How do chordomas clinically behave?

AnswerAlthough they grow slowly, chordomas are characterized by local destruction and multiple recurrences.  Complete surgical resection may be curative, but is extremely difficult to attain.  Radiation therapy may improve survival.

Question 11Name 2 other chordoid neoplasms of the CNS.

AnswerChordoid glioma of the third ventricle and Chordoid meningioma.